I can think of two useful little exercises that used to be standard student tasks.

Firstly, print each of the two split exposures separately, make two prints in other words, to see what they are doing to the 'hard' and 'soft' emulsions.

Second, make a grid of small prints (of the same photo) varying horizontally and vertically by exposure and by contrast, for example vary the exposure by a half of a stop over a +/- two stop range (in total, quartering and quadrupling the time of your 'standard' exposure) and change filtration by grades (having started with a print that works well at about Gd.2 and with a broad range of tones). Glue these small prints to a piece of board, with the 'normal' print in the middle, and that will give you a much better feel of what the effects of adjustments will be.